Whale poop contains iron that may have helped fertilize past oceans

The blue whale is the largest animal on the planet. It consumes enormous quantities of tiny, shrimp-like animals known as krill to support a body of up to 100 feet (30 meters) long. Blue whales and other baleen whales, which filter seawater through their mouths to feed on small marine life, once teemed in Earth's oceans. Then, over the past century, they were hunted almost to extinction for their energy-dense blubber.